Today, the IGBT (Insulated Gate Bipolar Transistor) is a popular semiconductor switch, which is available for power applications. There are three different types of the IGBT known as the PT-IGBT (Punch Through), the NPT-IGBT (Non-Punch Through) and the FS-IGBT (Field Stop).
Furthermore, conventionally a field stop zone is formed within a substrate by thinning the substrate to a precise thickness, implanting an “end-type” dopant, such as phosphorous or arsenic, into the bottom surface of the substrate, followed by high temperature anneal (usually at more than about 600° C.) to activate the dopant. It is known that multiple proton implantations can be used to produce a field stop zone. Here, hydrogen is implanted into a predetermined depth of a substrate, where the hydrogen behaves as an n+-dopant after the implant damage is annealed out. Implantation energies are usually less than 500 keV. Also, donors are generated in a so called “end-of-range region” of the semiconductor device, as well as any other region effected by the proton implantation. Here, the higher the proton implantation energy, the more donors are generated.
Therefore, it is advantageous that a field stop zone, especially within IGBT semiconductor devices, is formed in such a way as to create a sufficient junction barrier within the semiconductor device and having adequate dynamic properties.